Symmetric Iterations with Countable and $<\kappa$-Support: A Framework for Choiceless ZF Extensions
Abstract
We develop a unified framework for iterated symmetric extensions with countable support and, more generally, with -support. Set-length iterations are treated uniformly, and when the iteration template is first-order definable over a Godel-Bernays ground with Global Choice, the construction extends to class-length iterations. At limit stages with we use direct limits; when we use inverse-limit presentations via trees of conditions together with tuple-stabilizer symmetry filters. The resulting limit filters are normal and -complete, yielding closure of hereditarily symmetric names and preservation of . Under a -Baire (strategic closure) hypothesis we obtain , and under a Localization hypothesis we obtain . In the countable-support setting we give an -length construction adding reals and refuting while preserving , and we treat mixed products via stable pushforwards and restrictions. For singular , we develop the case using block-partition stabilizers and trees; for arbitrary singular we introduce game-guided fusion of length and a tree-fusion master condition, obtaining singular-limit completeness, preservation of , no collapse of , and no new subsets of any .
Keywords
Cite
@article{arxiv.2511.07866,
title = {Symmetric Iterations with Countable and $<\kappa$-Support: A Framework for Choiceless ZF Extensions},
author = {Frank Gilson},
journal= {arXiv preprint arXiv:2511.07866},
year = {2026}
}
Comments
Replaced in the countable case by arXiv:2601.11008, flawed in the uncountable cases